FrameTree::Find only searches relative to local frames.

third_party/WebKit/public/web/WebLocalFrame.h

Index: third_party/WebKit/public/web/WebLocalFrame.h
diff --git a/third_party/WebKit/public/web/WebLocalFrame.h b/third_party/WebKit/public/web/WebLocalFrame.h
index 1b3565dcc35deb0a0546921e9fc0f24df720aff1..434e0f687bb7b224137d00c5fdce1d2bca47e8ba 100644
--- a/third_party/WebKit/public/web/WebLocalFrame.h
+++ b/third_party/WebKit/public/web/WebLocalFrame.h
@@ -116,6 +116,11 @@ class WebLocalFrame : public WebFrame {
   // Get the highest-level LocalFrame in this frame's in-process subtree.
   virtual WebLocalFrame* LocalRoot() = 0;
 
+  // Returns the frame identified by the given name.  This method supports
+  // pseudo-names like _self, _top, and _blank and otherwise performs the same
+  // kind of lookup what |window.open(..., name)| would in Javascript.
+  virtual WebFrame* FindFrameByName(const WebString& name) = 0;
+
   // Navigation Ping --------------------------------------------------------
 
   virtual void SendPings(const WebURL& destination_url) = 0;